Electrical study of Schottky-barrier heights on atomically clean p-type InP(110) surfaces

N. Newman, M. Van Schilfgaarde, W. E. Spicer

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44 Scopus citations


We report here a systematic study of the electrical properties of a large number of metal (Ag, Cr, Cu, Au, Pd, Mn, Al, Ni) on p-type InP diodes. Schottky-barrier diodes were fabricated by in situ metal deposition on atomically clean InP(110) surfaces in ultrahigh vacuum. Schottky-barrier heights were determined from current-voltage (I-V) and capacitance-voltage (C-V) measurements. A small, but finite, range in barrier heights (0.760.98 eV) is found for the metalp-type InP systems investigated. When a comparison is made to our earlier work on n-type surfaces, we find that the interface Fermi level of n-type and p-type samples pins at the same position within the band gap for each of the metal InP systems studied. Our experimental results indicate that models that use metal-independent surface states (energy and density) and potential normalization conditions (i.e., natural band lineups) can predict the general trends in the interface Fermi-level pinning behavior. They cannot, however, successfully predict the details of this behavior to within measurement error. A theoretical method to determine the natural band lineups at the interface (using a scheme developed by Anderson) is presented within this context. Also investigated was the effect of air exposure on the electrical characteristics of diodes. For in situ I-V measurements, the metal semiconductor systems were characterized by a near-unity (1.031.10) ideality factor n. Upon exposure to air, a large increase in the current and ideality factor n was found for several (Cu, Au, Pd, Mn, Ni) metalp-type InP systems at all measured biases. A detailed investigation of the Pdp-type InP system indicated that the excess current pathway which results from exposure to air is at the periphery and can be eliminated by mesa etching.

Original languageEnglish (US)
Pages (from-to)6298-6304
Number of pages7
JournalPhysical Review B
Issue number12
StatePublished - Jan 1 1987
Externally publishedYes

ASJC Scopus subject areas

  • Condensed Matter Physics


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